Drawings/Graphs/Charts
A graph is a chart or drawing that shows the relationship between
changing things. They are diagrams displaying the relationship between
numbers or amounts. Common graphs use bars, lines, or parts of a circle
to display data.
When should we use drawings/graphs/charts?
- Use graphs to display data, to aid in understanding and interpreting
data, and to manage facts. You may also use graphs to illustrate targets,
goals and benchmarks.
- Use graphs to present facts in visual form. They are drawings that
display the relative sizes of numerical quantities. A graph is one
of the easiest ways to compare numbers.
- Use graphs to illustrate many types of data and are not limited
to the simpler types such as line, bar, and pie. They should be used
to make facts clearer and more understandable.
Figure |
Chart Type |
Use/Function |
 |
Bar charts
make it easier to recognize small differences in quantities and
to compare one category with another. They are easy to construct. |
To compare two (2) or more sets of data. |
 |
Line graphs
make trends and data variations over a period of time easy to
track. They highlight changes and can track more than one set of
data at a time. |
To show trends or patterns over a period of time. |
|
Pie charts
show relative proportion of each category to the whole. |
To show contributions of parts to a whole |
What makes a good graph?
- It accurately shows the facts.
- It grabs the readers’ attention.
- It shows trends or changes.
- It is clear and easy to read.
- It has a title.
It has labels for the x- and y-axes.
- It has a label for the origin, the point where the x-
and y-axes meet.
- It uses colors and patterns to show differences.
- It uses appropriate font sizes.
- It should be large enough to be readable.
What are the elements of a good graph?
A good graph should indicate:
- when the data were gathered;
- where the data were gathered;
- who gathered the data;
- whether they are raw data, percentages, or averages; and
- how the data were calculated (a formula).
How do we develop a graph?
- The scale used in a graph can be adjusted to show the situation.
It can be expanded to emphasize variation or compressed to show control.
All graphs should indicate the total number of data points represented.
If all the data points (the “population”) are represented,
this is indicated by a capital N =____. A sample number is indicated
by a lowercase n =____.
- It is generally considered good practice to include the “0”
(zero) point. If you want to magnify some portion of the graph to
show detailed variation, show the “0” (zero) point and
indicate a departure from the scale with some wavy lines.
- If there is a “good” direction, indicate this with an
arrow. (For example, an arrow pointed up would indicate that a high
mark on the y-axis is desirable, perhaps indicative of large
profits.)
What are the types of graphs?
|
